Method of manufacturing mounting pads for energy absorbing steering column installations

ABSTRACT

A method of manufacturing mounting pads for energy absorbing steering columns from a flat continuous ribbon of plastically deformable stock, as for example cold rolled steel, the method including the steps of forming a plurality of lugs along each edge of the ribbon at predetermined intervals along the length thereof, bending the lugs at right angles to the plane of the ribbon to define thereon a plurality of channel sections, severing the ribbon at predetermined intervals to define a plurality of pad blanks each including a pair of channel sections, and bending the blanks at right angles to the plane of the ribbon to define closed polygons each having a pair of opposite sides on which are disposed respective ones of the pair of channel sections, each channel section opening outwardly with respect to the interior of the closed polygon.

United States Patent 11 1 Brezinski et al.

1111 3,795,033 1451 Mar. 5,1974

[54] METHOD OF MANUFACTURING 3,531,861 10/1970 Golbeck 29/417 X MOUNTINGPADS FOR ENERGY ABSORBING STEERING COLUMN Prir nary ExaminerCh arles W.L anham INSTALLATIONS Asszstant Exammer-Ywtor A DiPalma Attorney, Agent,or F1rmSaul Schwartz [75] Inventors: Richard R. Brezmskl, Saginaw; LyleH. Durkee, Hemlock, both of Mich. ABSTRACT Assignee! 9 Corporafion, Amethod of manufacturing mounting pads for energy Detrolt, Mlchabsorbingsteering columns from a flat continuous rib- [22] Filed: Man 16 9 bon ofplastically deformable stock as for example cold rolled steel, themethod including the ste s of P PP 342,045 forming a plurality of lugsalong each edge of the ribbon at predetermined intervals along thelength [52] ll-S. Cl. 29/417, 29/DIG. 3, 1 13/1 16 H thereof, bendingthe lugs at right angles to the plane of [51] Int. Cl 823p 17/00 the"bbon to define thereon a Pluramy of channel [58] Field of Search29/417, 412, DIG. 3; Seve'mg ribbn predetermind to define a plurallty ofpad blanks each mcludmg al13/ll6l-l,116HH pair of channel sections, andbending the blanks at [56] References Cited riglht angles t; :lhe plane0t thte ribbon to djefine chases UNITED STATES PATENTS po ygons eac avmga pair 0 oppos1te s es on w 1c v are disposed respective ones of thepair of channel 537,505 4/1895 Van Dorn .1 29/417 X Sections eachchannel saction Opening outwardly i 343:55 respect to the interior ofthe closed polygon. 314173536 12/1968 Jakewaymu 29/417 x 3 Claims, 9Drawing Figures /fl W W UI'IIHI' I 111- 4 1 b *4 11 |.-1l 1 1 ILIHL. i i1 M11. l i ii/hi1.

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d 11 v @1115 11111 11 1111: 11111 0 Llirw/nv -Tmm |l1|||1 1l||1 i #J /fQ; 20 4 y METHOD OF MANUFACTURING MOUNTING PADS FOR ENERGY ABSORBINGSTEERING COLUMN INSTALLATIONS This invention relates generally tovehicle steering column installations and, more particularly, to amethod of manufacturing a mounting pad adapted for disposition betweenan energy absorbing steering column assembly and a fixed portion of avehicle body structure.

A typical energy absorbing steering column assembly includes a lowerportion adapted for fixed attachment to a vehicle body and a movableupper portion adapted for axial collapse in an energy absorbing modeunder impact. The upper portion is rigidly attached to the vehicle bodyfor normal steering operation through a connection adapted to release orgive way when the steering column assembly is sufficiently impacted atthe steering wheel end. In many modern vehicles the releasableconnection includes a mounting pad which is rigidly attached to thevehicle body and slidably supported on a bracket portion of the steeringcolumn assembly, themounting pad normally being of die cast constructionand attached to the bracket portion through a plurality of injectionmolded plastic pins adapted for fracture upon impact to the columnassembly. Die casting and plastic injection molding, relative to someother known manufacturing techniques, are expensive. A mounting padmanufacturing method according to this invention simultaneouslyeliminates both the die casting and injection molding operations and,accordingly, presents the possibility of substantial manufacturingeconomies.

The primary feature, then, of this invention is that it provides animproved method of manufacturing mounting pads for energy absorbingsteeringcolumn installations. Another feature of this invention is thatit provides an improved manufacturing method which enables thefabrication of mounting pads from a continuous ribbon of plasticallydeformable stock, as for example cold rolled steel, thereby facilitatingthe employment of high volume, relatively low cost stamping techniques.Yet another feature of this invention is that it provides an improvedmethod of manufacturing mounting pads wherein the continuous ribbon ofstock undergoes a first forming step wherein a plurality of lugs areformed along each edge at predetermined intervals, a second forming stepwherein the lugs are bent at right angles to the plane of the ribbon todefine thereon a plurality of channel sections, a third forming stepwherein the ribbon is severed at predetermined intervals, and a fourthstep wherein --the severed ribbon sections are bent to form a closedloop having a pair of channel sections projecting outwardly in oppositedirections.

These and other features of this invention will be readily apparent fromthe following specification and from the drawings wherein:

FIG.'1 is a perspective view ofa mounting pad manufactured in accordancewith this invention;

FIG. 2 is a view depicting the successive procedures comprising themanufacturing method according to this invention;

FIG. 3 is an enlarged sectional view taken generally along the planeindicated by lines 33 in FIG. 2;

FIG. 4 is an enlarged sectional view taken generally along the planeindicated by lines 44 in FIG. 2;

FIG. 9 is a view of a portion of FIG. 7 showing a mounting pad receivingslot in a bracket portion of the steering column assembly.

Referring now to FIGS. 1 and 2, and describing first the mounting padand the method or procedure according to this invention by which thelatter is manufactured and then the installation and operation thereof,a continuous ribbon 10 of plastically deformable stock, as for examplecold rolled steel, of predetermined width and thickness is introducedinto any appropriate forming machine which, as a first step in themanufacturing procedure, pierces the ribbon for effecting the removal ofa plurality of strips of material from along each edge of the ribbon. Asseen best in FIG. 2b, the strips are removed at intervalsalong thelength of the ribbon so that there is defined along one edge of theribbon a plurality of predeterminedly spaced short lugs 12, and alongthe opposite edge a corresponding plurality of predeterminedlyspacedlong lugs 14. The long and short lugs are arranged in pairs atpredetermined intervals along the length of the ribbon l0 and the lugscomprising each pair are disposed symmetrically with respect to atransverse plane oriented perpendicularly with respect to the plane ofthe ribbon, the transverse planes being disposed at predeterminedintervals corresponding to the intervals between the succeeding pairs oflugs 12 and 14.

As seen best in FIG. 2c, in the second step of the manufacturingprocedure the continuous ribbon 10 with the lugs 12 and 14 thereon issubjected to a second forming operation wherein each of the lugs isdistorted or bent to a position disposed perpendicularly with respect tothe plane of the ribbon 10. The width of the ribbon and the length ofthe lugs 12 and 14 are predetermined so that when the lugs are disposedperpendic ularly to the plane of the ribbon, the latter cooperate withthe portion of the ribbon therebetween in defining a plurality ofchannel sections 16., FIGS. 3 and 4, of predetermined depth.

Referring to FIG. 2d in the third step of the manufacturing procedurethe continuous ribbon 10 is severed at predetermined intervals along itslength thereby to define a plurality of flat pad blanks 18. Each blankincludes a pair of parallel ends 20 and a pair of channel sections 16 asdefined by two pairs of lugs 12 and 14.

As seen best in FIGS. 1, 2e, 4 and 5, in the final step of manufacturingprocedure the flat pad blank 18 is permanently distorted, as by bending,in a direction perpendicular to the plane of the ribbon 10 into asubstantially closed loop with the parallel ends 20 being brought togenerally abutting relationship. The closed loop may assume a number ofdifferent polygonal configurations but in the preferred embodiment. FIG.1, assumes the shape of a parallelogram having a pair of ends 22 and apair of sides 24. The longitudinal spacing between the two channelsections 16 on each pad blanks 18 is predetermined to insure that whenthe blank is distorted into the parallelogram configuration the channelsections are disposed centrally on each side 24, each channel section16, of course, opening outwardly with respect to the interior of theparallelogram.

The end result, then, of the manufacturing procedure according to thisinvention recited hereinbefore is a mounting pad designated generally 26fabricated through a plurality of relatively simple steps from thecontinuous ribbon 10. Each pad 26, FIGS. 1, 4 and 5, is of predetermineddepth and includes a top edge 28, a bottom edge 30, and the pair ofoutwardly extending channel sections 16 also of predetermined depth.

Referring now to FIGS. 6 through 8 and describing the environment andoperation of the pad 26, the latter is adapted for application in anenergy absorbing steering column installation 32 in a vehicle body 34.The vehicle body, shown in fragmentary partially broken away view inFIG. 6, includes interiorly thereof a rigid firewall 36 separating theengine compartment of the vehicle from the passenger compartment. Thefire wall 36 includes an aperture 38 through which projects the lowerportion of a collapsible steering column assembly 40. The steeringcolumn assembly 40 is generally conventional and includes a lowerportion 42 adapted for rigid anchorage on the tire wall 36 through aplate assembly 44 bolted to the tire wall. The'steering column assemblyfurther includes an upper portion 46 connected to the lower columnportion 42 through a corrugated metal section 48. The corrugated section48 normally maintains the upper column portion 46 in rigid relation tothe lower column portion 42. In the event of a substantial axiallydirected impact on the upper column portion the corrugated section 48 isadapted for plastic deformation which effects energy absorption andpermits axial collapse of the upper column portion 46 relative to thelower column portion 42. Rearwardly of the tire wall 36 there isdisposed transversely across the passenger compartment an instrumentpanel structure designated generally 50 and forward of the instrumentpanel structure there is disposed a rigid bracket assembly 52 adapted asdescribed hereinafter for cooperation with mounting pads manufactured inaccordance with this invention in releasably supporting the upper columnportion 46 on the vehicle body. I

As seen best in FIG. 7, the upper column portion 46 includes acylindrical mast jacket 54 connected at its lower end to the corrugatedsection 48 and at its upper end to a hub 56. A cylindrical shift tube 58is rotatably disposed within the mast jacket 54 for manual manipulationin a conventional manner by a shift lever and shift bowl assembly, notshown, rotatably disposed on the-hub 56. A steering shaft 60 isrotatably disposed within the shift tube 58 and is connected at itsupper end to a steering hand wheel 62 disposed outboard of the hub 56and at its lower end forward of the tire wall 36 to the vehicle steeringgear, not shown.

Referring now to FIGS. 6, 7, 8 and 9, the mast jacket 54 has rigidlyattached thereto an instrument panel bracket 64 adapted as describedhereinafter for releasable connection to the bracket assembly 52 on thevehicle body. The instrument panel bracket 64 is generally U-shaped inconfiguration and includes a main body portion 66 embracing and rigidlyattached to the mast jacket 54 and a pair of laterally spaced outwardlyextending wing flanges 68. Each wing flange has formed therein agenerally rectangular slot 70 opening rearwardly with respect to thedirection of axial collapse of the upper column portion 46. Each slotincludes a pair of side edges 72 extending generally axially of thesteering column assembly. At the open ends of the slots 70, each side 72thereof is extended by a tab 74 integral with the wing flange 68. Theinstrument panel bracket 64 is located axially along the mast jacket 54such that in an uncollapsed condition of the steeringcolumn assembly,FIGS. 6, 7 and 8, the instrument panel bracket is disposed injuxtaposition with a flange portion 76 of the bracket assembly 52.

The bracket assembly 52 further includes a pair of laterally spaced andgenerally vertically oriented rods 78 which are rigidly attached to thevehicle body forward of the instrument panel structure 50 and whichproject downwardly through appropriate apertures in the flange portion76 of the bracketassembly, each of the rods having a threaded portion 80extending beyond the lower surface of the flange portion 76, FIG. 8. Theslots 70 in the wing flanges 68 on the instrument panel bracket are 7adapted for registry with the threaded portions 80 of the rod so that inthe uncollapsed condition of the steering column assembly the rods aredisposed generally centrally in the slots, FIGS. 7 and 8.

Those skilled in the art will recognize, of course, that axial collapseof the upper column portion 46 effects forward movement, FIG. 6, of theinstrument panel bracket 64 relative to the flange portion 76 on thebracket assembly 52. Mounting pads 26 manufactured in accordance withthis invention function as releasable connectors betweenthe steeringcolumn assembly 40 and the vehicle body 34 to permit vehicle controlunder normal circumstances and collapse of the column assembly'underabnormal circumstances. More particularly, and with reference to FIGS. 1and 6 through 9, each slot 70 in the instrument panel brakcet 64slidably receives one of the pads 26. The. depth of the channel sections16 on the pads is predetermined to substantially equal the thickness ofthe wing flanges adjacent the slots 70 so that the pads slide easily inthe slots. The pads are retained vertically relative to the wing flangesby the lugs 12 and 14 which engage the flange from above and below,respectively. The pads are retained longitudinally relative to the wingflanges by the tabs 74 l which are crimped over behind the pads afterthe latter are installed in the slots 70.

As seen best in FIGS. 7 and 8, with the pads 26 installed and thesteering column assembly in the uncollapsed condition, the rods 78project through corresponding ones of the pads when the instrument panelbracket is brought into juxtaposition against the flange portion 76 ofthe bracket assembly 52. Threaded portion 80 on each rod receivestherearound a washer 82 and a nut 84, the washer being retained on therod by the nut. The nuts function to clamp the mounting pads tightlybetween the flange portion 76 and the washers 82, the flange portionengaging the top edge 28 of the pad and the washer engaging the bottomedge 30 of the pad. Accordingly, the pads 26 are rigidly attached to afixed portion of the vehicle body structure and, in turn, normallyrigidly connect the instrument panel bracket 64 on the steering columnassembly to the vehicle body structure.

Under normal operating conditions, the steering column assembly 40,rigidly supported by the rods 78 through the pads 26, functions in aconventional manner to control the direction of the vehicle in responseto manual input at the steering hand wheel 62. ln the event of theforwardly directed impact on the wheel 62, the upper column portion 46is urged forwardly. The pads 26, however, being rigidly clamped to theflange portion 76 of the bracket assembly 52 are restrained againstsimilar forward movement so that, at a predetermined force level, thetabs 74 give way to permit the instrument panel bracket 64 to moveforward with the upper column portion, the pads 26 simultaneouslysliding out of the open end of the slots 70.

Having thus described the invention, what is claimed l. A method ofmanufacturing a mounting pad for a collapsible steering column assemblyfrom a continuous flat ribbon of plastically deformable stock ofpredetermined width and thickness comprising the steps of, forming oneach edge of said ribbon a plurality of integral lugs disposed atpredetermined intervals along the length of said ribbon, bending each ofsaid integral lugs to a position disposed generally perpendicular to thebending each of said pad blanks in a direction perpendicular to theplane thereof to bring each of said ends into abutting relationship andsuch that a closed polygon is defined having a pair of opposite sideseach ineluding one of said channel sections, each of said channelsections opening outwardly with respect to the interior of said closedpolygon.

2. A method of manufacturing a mounting pad for a collapsible steeringcolumn assembly from a continuous flat ribbon of plastically deformablestock of predetermined width and thickness comprising the steps of,removing stock from each edge of said ribbon at predetermined intervalsalong the length of the latter thereby to define a plurality ofintegrallugs on each edge of said ribbon disposed at predetermined intervalsalong the length of the latter, bending each of said integral lugs to aposition disposed generally perpendicular to the plane of said ribbon sothat said integral lugs cooperate in defining a plurality of channelsections disposed at predetermined intervals along the length of saidribbon, severing said ribbon at predetermined intervals along the lengththereof thereby to define a plurality of flat pad blanks each includinga pair of parallel ends having a pair of said channel sections disposedtherebetween, and bending each of said pad blanks in a directionperpendicular to the plane thereof to bring each of said parallel endsinto generally abutting relationship and such that a closedparallelogram is defined having a pair of opposite ends and a pair ofparallel sides, each of said sides including one of said channelsections and each of said channel sections opening outwardly withrespect to the interior of said closed parallelogram.

3. The method recited in claim 2 wherein said integral lugs on each edgeof said ribbon are arranged in pairs spaced at predetermined intervalsalong the length of said ribbon, said integral lugs in each pair beingsymmetrical with respect to a corresponding one of a plurality of planesperpendicular to the plane of said ribbon and extending transversely ofthe latter at predetermined intervals along the length thereof.

1. A method of manufActuring a mounting pad for a collapsible steeringcolumn assembly from a continuous flat ribbon of plastically deformablestock of predetermined width and thickness comprising the steps of,forming on each edge of said ribbon a plurality of integral lugsdisposed at predetermined intervals along the length of said ribbon,bending each of said integral lugs to a position disposed generallyperpendicular to the plane of said ribbon so that said integral lugscooperate in defining a plurality of channel sections disposed atpredetermined intervals along the length of said ribbon, severing saidribbon at predetermined intervals along the length thereof thereby todefine a plurality of flat pad blanks each including a pair of endshaving a pair of said channel sections disposed therebetween, andbending each of said pad blanks in a direction perpendicular to theplane thereof to bring each of said ends into abutting relationship andsuch that a closed polygon is defined having a pair of opposite sideseach including one of said channel sections, each of said channelsections opening outwardly with respect to the interior of said closedpolygon.
 2. A method of manufacturing a mounting pad for a collapsiblesteering column assembly from a continuous flat ribbon of plasticallydeformable stock of predetermined width and thickness comprising thesteps of, removing stock from each edge of said ribbon at predeterminedintervals along the length of the latter thereby to define a pluralityof integral lugs on each edge of said ribbon disposed at predeterminedintervals along the length of the latter, bending each of said integrallugs to a position disposed generally perpendicular to the plane of saidribbon so that said integral lugs cooperate in defining a plurality ofchannel sections disposed at predetermined intervals along the length ofsaid ribbon, severing said ribbon at predetermined intervals along thelength thereof thereby to define a plurality of flat pad blanks eachincluding a pair of parallel ends having a pair of said channel sectionsdisposed therebetween, and bending each of said pad blanks in adirection perpendicular to the plane thereof to bring each of saidparallel ends into generally abutting relationship and such that aclosed parallelogram is defined having a pair of opposite ends and apair of parallel sides, each of said sides including one of said channelsections and each of said channel sections opening outwardly withrespect to the interior of said closed parallelogram.
 3. The methodrecited in claim 2 wherein said integral lugs on each edge of saidribbon are arranged in pairs spaced at predetermined intervals along thelength of said ribbon, said integral lugs in each pair being symmetricalwith respect to a corresponding one of a plurality of planesperpendicular to the plane of said ribbon and extending transversely ofthe latter at predetermined intervals along the length thereof.